Development of a DNA-Based Real-Time PCR Assay To Quantify Allorhizobium vitis Over Time in Grapevine (Vitis vinifera L.) Plantlets.

Allorhizobium vitis is the primary causal pathogen of grapevine crown gall disease. Because this endophytic bacterium can survive as a systemic latent (symptomless) infection in grapevine, detecting and monitoring its development in planta is of great importance. In plant bacteria studies, plate counting is routinely used as a simple and reliable method to evaluate the bacterial population level in planta. However, isolation techniques are time-consuming and present some disadvantages such as the risk of contamination and the need for fresh samples for research. In this study, we developed a DNA-based real-time PCR assay that can replace the classical method to monitor the development of Allorhizobium vitis in grapevine plantlets. Primers targeting Allorhizobium vitis chromosomic genes and the virulent tumor-inducing plasmid were validated. The proposed quantitative real-time PCR technique is highly reliable and reproducible to assess Allorhizobium vitis numeration at the earliest stage of infection until tumor development in grapevine plantlets. Moreover, this low-cost technique provides rapid and robust in planta quantification of the pathogen and is suitable for fundamental research to monitor bacterial development over time.

Comparative analysis of the responses to water stress in eggplant (Solanum melongena) cultivars.

Little information is available on the physiological and biochemical responses to water stress in eggplant (Solanum melongena). We evaluated four genetically diverse eggplant varieties (MEL3-MEL6) under control and water stress conditions. Measurements were taken for plant growth, tissue water content, levels of chlorophylls a and b, carotenoids, proline, malondialdehyde, total phenolics, total flavonoids, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities. For most traits, the water stress treatment had a greater contribution than the variety effect to the total sums of squares in an ANOVA analysis, except for total flavonoids, SOD, APX, and GR. The water stress treatment had a strong effect on plant growth and tissue water content. In general, water stress reduced the three photosynthetic pigments, increased proline, malondialdehyde, total phenolics, and total flavonoids, although some varietal differences were observed. Different patterns were also detected in the activities of the four enzymes evaluated, but few differences were observed for individual varieties between the control and water stress treatments. Many significant phenotypic correlations were observed among the traits studied, but only eight environmental correlations were detected. A PCA analysis distinctly separated individuals according to the treatment, and revealed a clearer separation of varieties under water stress than under control conditions, pointing to varietal differences in the responses to stress. Our results suggest that proline could be used as a marker for drought stress tolerance in this species. The information obtained provides new insight on the physiological and biochemical responses of eggplant to drought stress.

α-Glucosidase Inhibitory and Cytotoxic Taxane Diterpenoids from the Stem Bark of Taxus wallichiana.

From a CH2Cl2 extract of the bark of Taxus wallichiana, six new taxoids, wallitaxanes A-F (1-6), were isolated, together with 29 known compounds. The structures of the new compounds were elucidated on the basis of spectroscopic data interpretation. Wallitaxane D (4) was identified as an opened oxetane-type taxoid having the first naturally occurring C(H)-20 acetal group, while wallitaxanes E (5) and F (6) are representative of the rare abeo-taxoid class. The isolated compounds were evaluated for their α-glucosidase inhibitory activity and for cytotoxicity against the HeLa human cervical cancer cell line. In the present work, taxanes were found to exhibit α-glucosidase inhibitory activity for the first time, and wallitaxane A (1) showed the most potent effect, with an IC50 value of 3.6 µM. In turn, 7-epi-taxol (16) and 7-epi-10-deacetyltaxol (17) showed IC50 values of 0.05 and 0.085 nM, respectively, against HeLa cells.

Dehydrosulfurative C-N Cross-Coupling and Concomitant Oxidative Dehydrogenation for One-Step Synthesis of 2-Aryl(alkyl)aminopyrimidines from 3,4-Dihydropyrimidin-1H-2-thiones.

A method for the synthesis of 2-aryl(alkyl)aminopyrimidines from readily available 3,4-dihydropyrimidin-1H-2-thiones (DHPMs) via dehydrosulfurative C-N cross-coupling and concomitant oxidative dehydrogenation under a Pd/Cu catalytic system is described. This reaction protocol provides unprecedented diversity of fully substituted 2-aryl(alkyl)aminopyrimidines in a single step from a wide range of DHPMs and amine coupling partners.